Comentario de Ardinur

You can get loot from each rare spawn once per character per day, so you essentially have four chances to get the cage each day. Killing all four rare spawns that can drop the cage also gives you the achievement Azote infernal.

Each cage you open has a 1/3 chance to give you one of the following mounts:

Comentario de SerroDan

All 4 of the rares have the same minimum and maximum spawn timer this being between 1-3 hours.

When each of these rares spawn, a yell is put into the chat log and 3/4 of them will play a zone sound

When Horropuño spawns no sound is played, but the Yell that is pasted into chat follows: "Frogan Yells: A massive gronnling is heading towards the Rangari Refuge! We are going to require some assistance!"

They don't however drop the mounts 100% of the time. In fact they don't even drop the mounts themselves, they actually drop a cage (Jaula de hierro ruidosa) which drops the mount. The drop chance of this cage is 15% from all of the rares.

There are also 3 mounts to get from this cage! Each mount has an equal chance (1/3) of coming out of the cage. This being so you can get the same mount twice, three times, or even more! These mounts are:

Comentario de Telar

Comentario de esmerelda1rm

I finally got the Tundra Icehoof yesterday! It took a total of 174 kills to get all three mounts. The Warsong Direfang dropped the most for me when I looted the Jaula de hierro ruidosa off the four rares in Tanaan Jungle.

Comentario de Thefireone

Had it today. Seems bugged? Activated it, it's not in my collection and it's not searchable in the mount search bar. It's not in my inventory either. Opened a ticket let's see how it turns out.

Update: I have the mount as in it's castable with /cast Tundra Icehoof but still not visible in my collection. Weird.

Comentario de Factum

Finally got this after 248 attempts! Got the 2 other mounts like 4 time each before i got this one :)

Comentario de Djongov

Ok in Legion these are nightmare for farming. They are getting insta killed. Hopefully in BFA they will die slower after the squish. They are quite hard actually on the BFA beta now. I am at 102 kills and missing the wolf only. Unfortunately, i got the 2 other mounts within my 1st 30 kills so after that it has been dry. Not a single cage from 30th kill until now (102 kills) so i too doubt that the cages drop at 11-15% drop. Perhaps 5%?

So i have been having this semi-useful tactic. Whenever i arrive in the Tanaan Jungle i am not sure which rare will spawn next. So i position myself in the crossline of all 4 which is not ideal because you are too far away from Doomroller but better than camping 1 slot and pray it is next.

So when the first one spawns you can adjust your waiting position to a more efficient one knowing that the one that just spawned is unlikely to spawn again next. They usually spawn in order (for example Doomroller, Deathtalon, Terrorfist and Vengeance) but sometimes although rarely i've seen disorder in spawn rotations like Deathtalon, Terrorfirst, Vengeance, Deathtalon, Doomroller, Terrorfist.

So in Legion this is the only advice i can give you. Apart from positioning the rest is luck. A lot of luck. First you need to get to the rare and for it to be alive, then you have to be lucky to drop a cage and then you pray that the mount inside is not one that you already have. I wish i farmed these more in WoD times.

To help out with some sort of notification when they spawn so you can start flying to their location immediately - I use SilverDragon. It notifies me immediately on the usual yell when they spawn as a point-of-interest type of rare notification. It is very useful although you can survive without it.

If you are unsure where they spawn, a lot of coords here in the comments but they also appear on the map right after the yelling for their spawn. Also HandyNotes addon for Draenor or Tanaan has them in useful icons just like in my screenshot above